Reversible pump for hydraulic hoists



- Jan. 23 1933. F. BESZANTZ REVERSIBLE PUMP FOR HYDRAULIC HOISTS I'll I I I I i l I I I l I I I I l I! Jan. 3 3.933 F. BISZANTZ REVERSIBLE PUMP FOR HYDRAULIC HOISTS Filed Jan. 22, l931 4 Sheets Sheet 4 Patented Jan. 3, 1933 UNIED STATES FRED BISZANTZ, E GALION, @2323, ASSEGNOR TO THE CENTRAL OHIO STEEL PBODUG'I'S PATENT OFFICE 00., OF GALION, GHIO, A OORPQBATION OF OHIO REVERSIBLE FOR HYDRAULIC HOISTS Application filed January 22, 1981.

This invention relates to trucks having tilting bodies and particularly those truclts wherein the body is tilted by a hydraulic hoist which includes a pump, a cylinder, and

a piston operating in the cylinder and operatively connected to the tilting body of the truck.

Motor truck frames usually have means in their transmission gear cases for attaching thereto another small housing containing gearing for transmitting power from the engine through proper shafts and universal joints for the purpose of driving other mechanis'ms, such as the hoisting mechanisms of 5 various types of dump bodies.

In some makes of trucks, these auxiliary driving shafts will run clockwise and in others they will run counter-clockwise. Where a gear pump is used, as in a hydraulic hoist for tilting the dump body, this differenoe in direction of rotation of the driving shaft will in one case drive the fluid in one direction and in the other case drive it in the opposite direction if the same pump is used. As a conse uence of this, manufacturers are compelle to furnish two different pump designs, providing in one case that the driving shaft connects to one of the gears while in the next case the shaft connects to the mating gear.

The general object of the present invention is to provide means whereby only one design of pump body need be used, whether the driving shaft turns in a clockwise or a counter-clockwise direction and more particularly to provide a combination of pump cover, pump body and cylinder head so constructed that if the driving shaft rotates in one direction, the pump body may be disposed in one position between the cover and the cylinder head, and if the driving shaft rotates in the other direction, the pump may be rota- .tively shifted between the cylinder head and cover into another position.

A further object is to provide a construction of this character wherein the cylinder head and the body of the pump have ports registerable with each other in two different positions of the pump body and concentri- Scrial N0. 510,531.

cally arranged with reference to the axial center of the pum body.

Other objects Wlll appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein Figure 1 is a longitudinal sectional view of a portion of the truck body and truck showing in elevation the elevating mechanism for the truck;

Figure 2 is a fragmentary perspective view of a portion of the frame of the truck, the body not being shown, but showing the manner in which the elevating mechanism is mounted upon this truck frame;

Figure 3 is a longitudinal section on the line 3-3 of Figure 5, the cylinder being shown in section;

Figure 4 is a fragmentary section on the line Jr-4; of Figure 3, the body of the pump being shown in elevation;

F igure 5 is a section on the line 55 of Figure 3;

igure 6 is an under side plan view of the elevatlng mechanism but showing the reversal in position of the pump body in relation to Figure 5;

Figure 7 is an elevation partly in section of one of the tubular bolts showing the check valve therein;

Figure 8 is a fragmentary section view through the valve and valve housing;

Figure 9 is an elevation of the valve;

Figure 10 is also an elevation of the valve but viewed at right angles to Figure 9.

Referring to these drawings, A indicates a supporting frame or chassis and B a body pivoted thereon for upward tilting movement on the shaft 6. C designates a power take-off shaft section connected by a universal joint to a horizontal power take-off section connected to any desired power take-off (neither of which are shown) in turn connected in a well-known manner to the engine of the truck. The particular form of the power take-off and its connection with the shaft sections forms no part of this present invention.

For the (purpose of tilting the body B I have shown an preferably use a cylinder 10 having therein a piston 11 and piston rod 12 pivotally connected to the body at 13. This linder head is tiltably mounted upon the c assis or supporting frame as, for instance, by a pivot shaft 14 extending across the bod and mounted in bearin s. The pivot sha t may be fixed and the cy inder swing relative thereto or the shaft may oscillate with the cylinder.

In order to support the cylinder on the shaft, I provide -a head 15 having formed therewith the eye 16 which embraces the shaft 14. The cylinder head 15 may be connected I to the cylinder in any suitable manner as by welding. The u per end of the cylinder is, of course, provi ed with the stuffing box 17 through which the piston rod passes, the cylinder being designed to contain oil as a preferable fluid medium by which the piston may be raised by pumping liquid into the lower end of the cylinder and out of the upper end of the cylinder above the piston or lowered by allowing the liquid to escape from the lower end of the cylinder into the upper end thereof or flow from the lower end of the cylinder into the upper end thereof. Hence the cylinder and its connection to the cylinder head must be liquid-tight.

Before detailing the construction of the established between the inlet 0 linder head, it is necessary to describe'the t e pump and its cover. The pump body, whose housing is designated generally 18 is a simple form of gear pump. Within the pump housing 18 are formed the two connected chambers 19 and 20 within which the two rotary intermeshing pump gears 21 and 22 operate. The pump gear 21 is mounted on a driving shaft 23 extending through a stuiling box in the cover 24 as will be later described. The outer end of this driving shaft is connected to the driving shaft of the auxiliary power take-off by any suitable means, as for instance, by a universal joint and the inner end of the driving shaft 23 is mounted in bearings 25 in the cover. The shaft of the pump gear 22 is mounted in bearings 26 and 27 formed in the housing 18 and cover 24 respectively. The housing or body 18 and cover 24 are formed with coinciding bolt holes whereby they may be held'in engagement by bolts 50.

Disposed in diametrically opposite relation on opposite sides of the gear 21 are the ports 28 and 29 extending entirely through the housing or body. From these ports, ducts 30 and 31 lead into the gear chambers at the intersection of the twochambers.

It is to be noted that the ports or bores 28 and 29 are each equi-distant from the axial center of the pump gear chamber 19 and that the cover 24 is also formed with two bores 32 and 33 in alinement with the ports 28 and 29.

The cylinder head section 15 is preferably a casting and formed to provide a recess 34 to receive the protuberant bearing 27 on the pump body. This head is formed with two downwardly opening ports 35 and 36, disposed the same distance from each other as the ports 28 and 29 so that either of the ports 28 or 29 ma be brought into alinement witheither o the ports 35 or 36. The port 35 opens directly into the cylinder. Formed on that face of the cylinder head toward the cylinder but to one side of th cylinder seat 37 is a laterally projecting valve casing 38 within which operates a valve 39 havin a stem 39. This valve casing is connecte on one side to the port 35 by a duct 40 and on the other side is connected to the port 36 by a duct 41, (see Fig. 4). This duct 41. does not connect directly with the port 36- but extends straight outward to and opens on the edge of the cylinder head and from the port 36 extends a duct 42 which intersects the duct 41 and connects port 36 therewith. The valve is provided with a single port 43 extending diametrically across the valve. When the valve is turned with the port 43 at right anglesto the ducts 40 and 41 as in Figure 8, passage from the duct 40 to the duct 41 is cut ofll- When the valve is turned so that the port 43 is in alinement with the ducts 40 and 41, a connection is v port 35 and the duct 41 and duct 42. The duct 41 at its extremity is operatively connected by any suitable connection to a sump 44 which may also be mounted upon the c linder head or connected to it in any suita le way or mounted upon the cylinder, the opposite end of this sump 44 having a pipe connection 45 to the cylinder port 46 at a point adjacent its upper end but below the upper end of the cylinder. The purpose of this sump is to provide means whereby the pump can secure liquid from the closed circulating system at the moment that the piston has moved upward to and blocked or cut off the opening 46 leading into pipe 45. If it were not for this sump, that is, if the pipe 45 led directly to the duct 41 and not into a relatively large sump or chamber, then when the piston closed cylinder port 46, the pump being unable to draw in any liquid from the upper end of the cylinder, the piston would stop and no more liquid could be forced into the lower end of the cylinder and the piston would not move outward any further but would stay at this point.

With my construction, however, when the piston reaches the opening 46 of pipe 45, and cuts oil the passage of liquid through'this opening 46, the pump will draw its feed from the sump 44 and the piston will continue its movement upward until it has passed the opening 46. As soon as this occurs, the liquid will circulate from the cylinder below the piston through the port 46 through the pipe 45 and sump 44 into the pump and then back a ain into the lower end of the cylinder tliroug the port 35 and a constant circulation will thus be kept up below the piston which will act to hold the piston raised and the body in its tilted position with the pump running or with the valve 39 closed.

This does away with the necessity of the operator stopping the pump when the body has been completely raised. If my construction were not use and the pump were not stop ed or disconnected from the power, there wou d be a likelihood of breakage. My construction, however, provides for the continuous operation of the pump after the body has been raised and tilted and no accident will happen even if the pump does continue to run.

It is to be noted that the cover and the vpump body are held together by screws 50.

These screws, however, do not pass into the cylinder head, hence it is necessary to insert tubular bolts 47 and 47* as shown in detail in'Figure 7 longitudinally through the holes or bores 32, 28 and 36 and 33, 29 and 35. These bolts have screw threaded engagement with the ports 35 and 36 in the cylinder head and at their lower ends carry heads, designated 48 for bolt 47 and 48 for bolt 47, which bear against the under face of the cover and thus hold the cylinder head, pump body and cover in liquid-tight engagement with each other. These tubular or sleeve bolts have perforations 49 which communicatively connect the ducts 30 and 31 with ports 35 and 36. The bolt 47 which constitutes an inlet duct is provided also with a check valve 51 as shown most clearly in Figures 3 and 7 permittlng the inlet of liquid to the interior of the cylinder but preventing back flow of liquid from the interior of the duct to the pump:

When it is desired to raise the body, the operator turns the valve 39 to a position where the port 43 isout of alinement with the ducts 40 and 41. The duct 41, as before stated, is connected to the sump. The port 36 is connected to the inlet end 29 of the pump. Hence if the valve 39 is closed and the pum operated, liquid will pass from ort 35 into the lower end of the cylinder,

rom the upper end of the cylinder back through the opening 46, pipe and sump 44 to duct 42 and so to inlet port 36' and back through port 28 and duct 30 to the pump. In case it be desired to lower the body, the valve 39 is opened by the operator. This directly connects the port 35 to the duct 41 and the sump so that instead of the liquid from the pump passing into the cylinder, it will pass into the duct 42 and back to the sump and the weight of the body will cause the downward movement of the piston which will force the liquid in the cylinder back through port 35, the duct 41, thence to the sump, and thence into the upper portion of the cylinder,

thus ermitting the body to lower of its own weig t. The pump may continue to operate even when the piston is fully lowered, but the by-pass forme by the opening of the valve 39 will permit the constant circulation of fluid through the pump without affecting the hoisting piston.

Of course, after the body is lowered, if the valve 39 be turned to its closed position, and the pump should continue its movement, it would again act to hoist the body and hold the body hoisted until the valve 34 was again opened to permit the descent of the body. Of

course, the operator is supposed to stop the operation of the pump when the body has fully descended and then to return the valve 39 to its closed position but by my mechanism, no harm will come even if the operator does not stop the pump.

1 have illustrated in Figures 3 and 5 the parts of the pump as arranged to operate when the shaft of the pump gear 21 is rotatable in a clock-wise direction, but if this pump and allied parts is to be used with an auxiliary drive and shaft which rotates in a counter-clockwise direction, it is only necessary to reversely dispose the pump body as shown in Figure 6 so that the port 29 will become the outlet port of the pump and the port 28 becomes the inlet port of the pump. This is rendered possible by the fact that the ports 35 and 36 are disposed exactly the same distance apart as the ports 28 and 29 and because, of course, the ports 32 and 33 are also d'sposed the same distance apart as the ports 28 and 29 and because the cylinder head is so formed that either of the ports 28 or 29 may be brought into alinement with either of the ports 35 or 36. The cover and the body of the pump are connected to each other by screws 50 so that they practically form one element, but the pump body is initially disposable either with its port 28 in register with the port 35 and its port 39 in register with the port 36 or with the port 29 in register with the port 36 or with the port 29 in register with the port 35 and the port 28 in register with the port 36. It will be understood, of course, that this adjustment is made initially depending entirely upon the direction of rotation of the auxiliary driving shaft for the pump and that once these parts are initially arranged or adjusted, no other rearrangement is necessary. Thus the same pump and cylinder connections may be used whether the auxiliary driving shaft runs clockwise or counter-clockwise, thus doing away with the necessity of manufacturers furnishing two different pump designs for diflerent makes of auxiliary driving mechanism.

Attention is called to the peculiar shape of the eye 16 which engages the shaft 14. As will be seen from Figure 3, this eye is not uniformly circular but the eye is constricted at diametrically opposite portions in the middle of the eye as indicated at 16. Thus this eye, while snugly fitting the shaft 14 in one direction, is rockable upon the shaft 14 later- I ally. Thus the cylinder is free to oscillate in a vertical plane on the 1%" shaft 14. This allows freedom of movement of the other end of the cylinder from right to left, sufficient to compensate for twists in the truck frame when dumping. It is particularly important that this cylinder should have this freedom of side movement to prevent bending of the piston rods as often times trucks in service dump with one wheel fifteen inches lower or higher than the other three wheels.

The pressure of the cylinder against the shaft 14 upon which it pivots is extremely hard to counteract or control and for the purpose of securing a firm support for the cylinder at all times, I have devised the construction shown in Figure 2 wherein two flat bars 52 extend longitudinally of the truck frameone on either side of the cylinder and as close as possible to the cylinder. The truck frame is intersected by the four cross members 53, 14, b and 56 and these members attach to or intersect the fiat bars 52. These bars will rest on a cross bar of the frame near the cylinder pivot bar 14 distributing both horizontal and vertical thrusts so that the cylinder is securely held in proper location.

I It is to be understood that the structureshown in Figure 1 is illustrative of a frame which may be placed upon the ordinary truck frame for thepurpose of supporting and mounting the cylinder and its allied parts.

I'claim:

1. In combination, a rotary pump body having intermeshing pump gears, a driving shaft engaging one of said gears, the pump body having two ports radially equi-distant from the driving gear of the pump and disposed diametrically opposite each other and extending parallel to the axis of the driving gear, and an element having two ports, the pump body being rotatively adjustable around the axial center of the pump driving gear to bring either of its ports into register with either of the ports of said element.

2. In combination, an element having two thereof, and a pump body separate from but attached to the element having two ports and pump gears, one of which constitutes the 7 driving gear, the two ports of the pump body being disposed equi-distantly from and diametrically with relation to the axis of the driving gear and being distanced from each other the same distance as are the ports of the said element wherebythe pump body is bodily rotatable through 180 and either port of the pump body is registrable with either port of the element, and means for holding the pump body attached to the element in either of its adjusted positions. 7

' 4. The combination with a gear pump body having a chamber, intermeshing gears disposed within the chamber, one of said gears having a drivin connection extending through the pump ody, the pump body having two ports disposed equi-distantly on each side of the driving gear axis of the pump and diametric with relation to the same and communicating with said chamber on opposite sides of the pump gears and extending parallel to the axes thereof, an element having two port openings placed the same distance apart as the ports on the pump body and diametrically with relation to the axial center of the element, the pump body being adjust-' able around the axis of the driving gear to bring either one of its ports into registry with either one of the ports of the element, bolts detachably holding the pump body in its adjusted position with relation to the element, and means in said element whereby the two ports of the element may be directly connected with each other to thereby permit the reversal of the direction of circulation through the element.

In testimony whereof I aflix my signature.

FRED BISZANTZ.

opposed ports. and a rotary pump body separate from but attached to the element having two diametrically disposed ports and two intermeshing gears, one of said ears constituting a driving gear, the pump ody being bodily rotatable through an angle of 180 around an axis perpendicular to the ele ment and common to the driving ear to bring either of the ports of the pump ody in register with either of the ports of the element. r

3. The combination with an element having an inlet port and an outlet port extending through the element at right angles to the face 

